    [Prior-Art 1] U.S. Pat. No. 6,097,703 A, “Multi-hop packet radio networks,” August 2000.    [Prior-Art 2] U.S. Pat. No. 6,659,947 B1, “Wireless LAN architecture for integrated time-critical and non-time-critical services within medical facilities,” December 2003.    [Prior-Art 3] US 2005/010 0045 A1, “Access points with selective communication rate and scheduling control and related methods for wireless local area networks (WLANs),” May 2005.    [Prior-Art 4] US 2005/007 8636 A1, “System and method of handling IP layer mobility in a wireless network,” April 2004.    [Prior-Art 5] US 2002/017 6390 A1, “Wireless mesh network node,” Nov. 2002.
Wireless technologies are applied to diverse applications. Increasingly, they are used to interface communications entities covering large geographic areas. Such applications comprise wireless surveillance cameras located on street lamps across many kilometers, wireless users gathering in large exhibition centers and wireless terminals located in vehicles traveling along stretches of highways. Furthermore, such applications of wireless technologies typically involve wireless entities that are geographically far from each other, but are logically united. For instance, wireless surveillance cameras all relate to a logical security system, wireless users in exhibition centers relate to a single or plurality of companies and wireless terminals on highways relate to a single or plurality of wireless service providers.
[Cost of Deployment]
There are a number of challenges with realizing such applications. The primary among them is the cost of deploying communications infrastructure units such as access points, wireless terminal points and base transceiver stations. Because of the geographic spread of wireless communications entities in these applications, a large number of infrastructure equipment are required. The costs of deploying such communications systems would therefore be tremendous and prohibitive.
Furthermore, given their spread across large areas, few wireless communications entities will be provided service by each of the communications infrastructure units. This results in limited use of the communications infrastructure.
Additionally, communications equipment units for large geographies require extensive cabling for interconnection. This is further exacerbated by the limitations of cable lengths, such as the 100 meters limit on Ethernet cable lengths. In these cases, switches or routers are used for extension. Naturally, these devices add costs to the realization of distributed wireless applications.
It is envisioned that there will also be increasing requirements for communications infrastructure units to be cost-effectively deployed over large geographies. The limitations of wired cables prevent such deployments.
[Complexity of Operation]
Related to the cost of the switches and routers, is the complexity of extending infrastructure control across such devices. Switches and routers are typically used to delimit network segments. When communications infrastructure units of a distinct logical network cross network segments, their control is complicated. This is due to Internet Protocol (IP) segments.
Another complexity issue is the presence of network address translator (NAT) devices. NATs have been deployed in communications networks to multiplex IP addresses in a local network segment with IP addresses in an external network segment. Additionally, NATs may incorporate firewalls to restrict communications exchanges.
It is clear from these points, that the complexity of deploying distributed wireless applications over geographically diverse communications network is tremendous.
[Current General Approach]
A current approach to addressing the problems of deploying geographically diverse wireless applications is the use of mesh networks. In such networks, communications equipment units and mobile wireless terminals are interconnected in a mesh structure. Each network entity acts as both traffic source or destination and as traffic relaying point. Mesh network entities comprise multiple antennas or radios in order to perform the dual tasks of transmission/reception and relaying.
[Problems with Mesh]
Mesh networks are characterized by the effectiveness of their routing mechanisms. Due to the distributed nature of mesh networks, each network entity must determine and establish efficient routes with its peers.
The diversity of traffic paths available in a mesh network makes route determination complex and time-consuming. Furthermore, with the plurality of available routes across different mesh paths, there is significant overhead in the form of path status message exchange overheads and processing overheads—to determine the most appropriate route for traffic. The overheads of route computation and management deter wide-spread deployments of mesh networks. Consequently, geographically distributed wireless applications are not well supported by mesh networks.
Furthermore, the inherent uncertainty of wireless links complicates the efficiency of mesh network routing mechanisms.
Such problems of limited communications equipment coverage, interconnection complexity, mesh network route complications and costs severely restrict the deployment of communications networks capable of supporting geographically distributed wireless networks and applications.
[Prior-Art 1] illustrates a method for extending the geographic range of communications network by means of opportunistic transmission by constituent mobile wireless terminals. According to the method, mobile wireless terminals monitor the status of their links and select a neighbour to whom link conditions are most favourable. However, such a method has no bounds of operation, which therefore makes it unpredictable and prone to errors or transmission loops.
[Prior-Art 2] presents a method for an access point of a communications network to operate in accordance to two protocols. This method allows an access point to change its operating protocol in accordance with the application needs of mobile wireless terminals. The method however does not extend the geographic scope of the communications network infrastructure to mobile wireless terminals beyond the direct reach of the access point.
[Prior-Art 3] illustrates a method for increasing traffic capacity of a communications network by means of scheduling transmission queues on the basis of different transmission rates. This method is limited to the operation of a single communications network entity and as such is not suitable for networks with large geographic scope.
[Prior-Art 4] presents a system in which an intermediate session node is used to buffer traffic for a mobile wireless terminal moving from a first to a second communications network. The intermediate session node serves to assist in the continuity of a communications session during a mobile wireless terminal's transition. This method is only applicable to a unidirectional stream from a communications network to a mobile wireless terminal. It is not suitable for the reverse stream.
[Prior-Art 5] presents a method for establishing mesh networks through the use of sectored antennas. These are used to distinguish between traffic transmission or reception and traffic relay. While each sector of an antenna helps in the creation of neighbourhood routes, the method does not overcome the problems of high operational complexity and costs.
The prior arts discussed insofar illustrate the lack of existing mechanisms to address the needs of geographically distributed wireless applications. In particular, these needs comprise simple, cost-effective establishment of communications and operation across large geographic areas while maintaining logical unity.